Field
Aspects presented herein provide techniques for rendering images.
Description of the Related Art
Rendering realistic images from virtual models requires accounting for light scattering events though the volumes of some models and the resulting light transport between points on the surfaces of the models. Such scattering, often referred to as “subsurface scattering,” is prevalent in translucent media such as human flesh and skin, snow, plastics, foods, cloth, and marble. Subsurface scattering tends to soften the features of media, cause colors to bleed within media, and permit light to diffuse across shadow edges. For example, the shadows in human ears may appear reddish rather than entirely black due to subsurface scattering effects.
For efficiency purposes, a diffusion approximation is typically used to render images which include subsurface scattering. Diffusion models approximate the cumulative effect of multiple scattering events within a volume, without simulating individual scattering events. Currently, the most widely used diffusion model is the dipole model, though other diffusion models have recently gained favor. These diffusion models make a number of simplifying assumptions, such as that the surface of the media is a flat surface bounding a slab of finite or semi-infinite thickness, that the media has a homogenous composition, and that the incident light is orthogonal to the surface, with the outgoing angle of the light out of the media often ignored.